One example of this is the red and black opisthosoma pigmentation with guanine deposits, showing the benefit of the visual effects of these color polymorphisms. Population structure, speciation, and phylogeny Close relatives At least nine species in the Hawaiian islands have been identified to be members of the T. grallator-clade based on the analysis of genitalia patterns. This clade is believed to have been colonized from the Americas and is closely related to the genus Exalbidion. The closest relatives of T. grallator are other Hawaiian species, such as Theridion posticatum, Theridion kauaiense, and Theridion californicum. In T. grallator as well as T. californicum, there is one inconspicuous morph (namely, Yellow in T. grallator) that is the most common and an assortment of less common and seemingly more conspicuous morphs. This "T. grallator clade" may be more closely related to the genus Exalbidion than to any other species currently classified in the genus Theridion. Molecular clock data estimates that T. grallator first diverged from its ancestors about 4.22 Ma. Most of the Hawaiian Theridion are believed to be closely related except for T. actitarase, which contains a number of common traits with the related Rugathodes genus. Similar traits include the palpal organ and certain genitalia features. There is another Theridion species, which remains unnamed, that also displays features that are distinct from most Hawaiian Theridion. However, this unnamed species does contain a few characteristics that resemble the T. grallator, namely, its long legs and abdominal shape. Thus, this unnamed Theridion species may have evolved under similar evolutionary pressures as T. grallator. Despite some variations in the bodily appearance of the Theridion species, there still remains a uniformity in sexual behavior. There is also a highly uniform web-building behavior and structure. There has been much debate on how to organize clades and construct an appropriate phylogenetic structure of Theridiidae, and work is still being done to properly classify these species. Genetic population structure The genetic bases of the abdominal color morphs of the T. grallator vary by island despite the actual abdominal color morphs having an identical appearance throughout the islands. On Maui, the color morphs of T. grallator originated from one locus while those on Hawai’i have at least two unlinked loci involved in the color polymorphisms. In addition, on Maui, all polymorphisms are attributed to individual alleles while on Hawai’i, there are two pairs of color morphs that may depend